It has been known for some time that drugs and medical instruments and implements have to be sterilized so that they will not cause patients to become ill from harmful bacteria when they are applied to the patients. Systems have accordingly been provided for sterilizing drugs and medical instruments and implements. The drugs and the medical instruments and implements are then stored in sterilized packages until they are ready to be used.
In recent years, it has been discovered that foods can carry harmful bacteria if they are not processed properly or, even if they are processed properly, that the foods can harbor such harmful bacteria if they are not stored properly or retained under proper environmental conditions such as temperature. Some of these harmful bacteria can even be deadly.
For example, harmful bacteria have been discovered in recent years in hamburgers sold by one of the large national hamburger chains. Such harmful bacteria caused a number of purchasers of hamburgers from stores in the chain to become sick. As a result of this incident and several other similar incidents, it is now recommended that hamburgers should be cooked to a medium state rather than to a medium rare or rare state.
Similarly, harmful bacteria have been found to exist in many chickens that are sold to the public. In view of a number of incidents which have occurred, it is now recommended that all chickens be cooked so that no blood is visible in the cooked chickens.
To prevent incidents such as discussed in the previous paragraphs from occurring, various industries have now started to plan for sterilizing foods before the foods are sold to the public. This is true, for example, of hamburgers and chickens. It is also true of fruits, particularly fruits which are imported from foreign countries.
The preferred embodiments may be used to sterilize different products including drugs and medical instruments and medical implements but are particularly adapted to be used for sterilizing foods. In sterilizing foods, it is important that the sterilization is sufficiently strong to kill harmful bacteria in the food but is not so strong as to kill beneficial bacteria in the foods.
In the preferred embodiments, a first robotic assembly transfers articles form carriers on a transport mechanism at a loading area to a first load conveyor. The conveyor transfers the articles to a process conveyor which moves the articles through a target region at a substantially constant speed. The load and process conveyors may be divided into two tracks. First and second radiation sources respectively disposed at first and second gaps on the process conveyor in the target region respectively irradiate the articles in opposite directions from positions above and below the articles. The process conveyor then transfers the articles to a second load conveyor. A second robotic assembly then transfers the articles to article carriers on the transport mechanism at an unloading area.
Articles on the tracks may be (a) diverged on the first load conveyor to separate the articles from the dividers, (b) converged on the process conveyor to minimize the width of the radiation sources and (c) diverged on the second load conveyor.
If one of the radiation sources is not operative, the other source may irradiate the opposite sides of the articles during article movements sequentially on the first tracks of the first load conveyor, the process conveyor and the second load conveyor and then sequentially on the second tracks of the first load conveyor, the process conveyor and the second load conveyor. The articles are inverted during their transfer from the first track of the second load conveyor to the second track of the first load conveyor.